Senator Scott Brown and Elizabeth Warren, in their highly anticipated first debate, wasted no time attacking each other heatedly as they tangled over her heritage, his tax record, and which candidate would help the struggling middle class.

Brown went after Warren from the opening seconds, saying she has not “passed a test” of character, truthfulness, and honor necessary to be a senator ­because she “checked the box” as a Native American when “clearly she’s not.”

Warren, in a later exchange, struck at the heart of her argument, accusing Brown of holding “98 percent of families hostage” to protect tax breaks for the wealthiest.

The Republican senator was more personal in his attacks than his Democratic challenger, who tried to tie him to select elements of his record. Brown repeatedly referred to Warren as “professor Warren” and seemed eager to get under her skin, while Warren, though also in attack mode, was less animated than she appears on the trail.

The debate did not appear to produce a seismic moment that would change the course of what has been a consistently tight race, but rather hewed closely to many of the same issues that the candidates have been emphasizing on the stump and in a cascade of competing television commercials.

Brown took swipes at ­Warren and her husband’s salaries and benefits at Harvard Law School, where they both teach, to make a point about the rising costs of higher education. He pointed out that she did not voluntarily pay a higher income tax rate, as is allowed on state forms, in an attempt to accuse her of hypocrisy.

Warren tried to align Brown with national Republicans, big oil, and the interests of millionaires and billionaires. She said that regardless of his moderate reputation, he would support a broader GOP agenda that would hurt the middle class and empower climate change skeptics to make environmental policy. She repeatedly tried to make the point that Brown’s election could swing Senate control to Republicans, a central theme in her campaign.

“I’m not going to raise taxes on our job creators . . . I’m going to fight for every taxpayer.”

Scott Brown, Republican senator

‘He defended the top 2 percent and the top 3 percent . . . And he will hold the other 98 percent of families hostage.’

Elizabeth Warren, Democratic challenger

Though Brown was elected as the “41st vote” to block President Obama’s health care law, the nationally contentious issue was never mentioned.

After a year of fighting through press releases and commercials, the candidates stood just feet away from each other in the WBZ-TV (Channel 4) studios in Brighton, in the first of four debates, this one moderated by political analyst Jon Keller.

Brown’s image as an affable political figure might have taken a hit with his needling of Warren. At the same time, he may have countered the criticism that he is a lightweight by lacing his responses with policy-­heavy language.

Warren, on the other hand, shelved the lecture-hall tone that has come under criticism, in favor of a methodical attack on Brown and his voting ­record. But in doing so, she may also have sacrificed some of the passion that has driven her campaign.

The fireworks started immediately, as Brown challenged Warren to release personnel ­records from Harvard Law to prove that she did not use undocumented claims of Native American heritage to advance her career. He pointed to evidence that Warren had listed herself as a Native American in legal directories and in official documents at the universities where she worked.

“Professor Warren claimed that she was a Native American, a person of color, and as you can see she’s not,” Brown said. “When you want to be a United States senator, you have to pass a test, and that’s one of character and honesty and truthfulness. . . . She’s failed that test.”

Warren did not agree to ­release the records. But she ­insisted “I never used it” and pointed to numerous past hiring deans, including former Reagan administration solicitor general Charles Fried, who have said her heritage played no part in her hiring.

“When I was growing up, these are the stories I knew about my heritage,” Warren said. “I never asked anybody for any documentation. I don’t know any kid that did.”

The debate, which was nearly canceled
because of concerns that Brown might be delayed by business in Washington, was carried locally by WBZ and ­nationally on ­C-Span.

Warren went back on the ­offensive when the argument turned to taxes, as both candidates threw out a slew of figures to paint the other as hostile to the middle class. Warren highlighted Brown’s vote over the summer against extending the Bush tax cuts for those making less than $250,000, and pointed to a statement he made last week that he would not agree to cast such a vote if there is no other alternative.

“Senator Brown voted no,” Warren said. “Because there weren’t enough tax breaks for the top 2 percent. . . . He will hold the other 98 percent of families hostage.”

Brown argued that he would not raise taxes on anyone during the tough economy, including those responsible for creating jobs. Those employers, he said, have been hampered in their efforts to grow because of uncertain tax and regulatory policy favored by Warren.

“The criticism that you’re hearing from
professor Warren and her supporters is that I don’t want to raise taxes,” he said. “Guilty as charged.”

The tax debate was again central to the candidates’ dispute over energy policy.

Brown insisted that gas prices would increase if they were removed, which could lead the country back into recession. He said it was typical of Warren’s approach to solving problems. “She’s obsessed with raising taxes,” Brown said.

The two also sparred over abortion, reproductive health, and other women’s issues, with Warren disputing Brown’s statement that he is a “moderate prochoice Republican.”

Warren criticized Brown for cosponsoring an amendment that would have allowed ­employers to deny coverage for birth control and other medical care if they had moral objections. Brown said it was a conscience objection that was in line with the beliefs of Edward M. Kennedy, who held the seat for nearly five decades. The late senator’s family disputes that contention. “Stop scaring women,” Brown said. “I’m not going to pit women against their church and their faith.”

Warren said it wasn’t a question of religious freedom. “This was really an open invitation for employers to say to insurance companies: ‘You can knock out birth control coverage for women,’ ” she said.

When Warren criticized Brown for voting against confirmation of Supreme Court Justice Elena Kagan, a former dean of Harvard Law and solicitor general, Brown made it personal again. “I’m sorry I didn’t vote for your boss,” he said. “I know that you and Justice Kagan are very close.”

He said his vote was based on Kagan’s lack of courtroom experience, not her support for ­legalized abortion.

Both candidates said they agreed climate change is real and a crisis. But Brown criticized Warren for opposing the Keystone pipeline, saying it will cost jobs. Warren said that regard­less of what Brown said about climate change, his reelection could give Republicans control of the Senate and elevate a climate change skeptic, James Inhofe, to lead the committee that oversees environmental policies.